The bill's requirements could be used either to help find a 911 caller who is using a cellphone or to detect the phone's location when there is the danger of death or serious physical injury.

Sponsoring Rep. Jeanie Lauer, R-Blue Springs, said the legislation was prompted by the killing of 18-year-old Kelsey Smith, who was abducted in 2007 outside a shopping center in Overland Park, Kan. Her body was found four days later.

Lauer said Smith might have been found faster if authorities had been better able to track her cellphone signals.